1. Field of the Invention
The present invention relates to a hybrid drive device which includes as drive sources an engine (for example, an internal combustion engine such as a gasoline engine, a diesel engine, or the like) and a rotary electrical machine (including, for example, a motor which receives supply of power to generate driving force (for example, rotational driving force), a generator which receives a supplied driving force to generate power, or a machine that works as a motor or generator selectively according to the operation state), and is structured to obtain driving force from one or both of the engine and the rotary electrical machine, shift the driving force with a transmission and transfer the shifted driving force to driving wheels.
2. Description of the Related Art
The applicants have introduced a hybrid drive device described in Japanese Patent Application Publication No. JP-A-2004-001708. An object of the technology disclosed in JP-A-2004-001708 is to provide a hybrid vehicle drive device having a structure in which, although an engine and a motor are coupled to be a drive source, the dimension in an axial direction is reduced further as compared to conventional devices and the dimension in a radial direction is not increased.
The hybrid vehicle drive device described in Japanese Patent Application Publication No. JP-A-2004-001708 includes an annular motor positioned about the axis of an engine output shaft, a starting device transferring driving force from the engine and the motor to a downstream transfer side, and a transmission to which the driving force from the engine and the motor is transferred via the starting device. In this drive device, the starting device includes a starting clutch and a damper device, which are formed in an annular shape about the aforementioned axis and arranged separate from each other by a predetermined distance in the axial direction, and the starting clutch is arranged so that at least a part thereof overlaps with the motor in the axial direction and is positioned on a more inside diameter side than the damper device. Japanese Patent Application Publication No. JP-A-2004-001708 shows an example of a hybrid drive device that can achieve the above object.
However, the support structure for the rotary electrical machine described above has a problem. In Japanese Patent Application Publication No. JP-A-2004-001708, a rotary electrical machine case, which is formed in a cylindrical shape and which accommodates the rotary electrical machine, is divided into two members. A partition wall is provided on the engine side case member, and a rotary electrical machine is provided on an inner peripheral portion of the transmission side case member. Therefore, in this structure, the divided case members are coupled via abutting faces thereof, and in the coupled state, the case members are coupled to the engine via a rear side thereof. Thus, they must also support the transmission as well, which requires high strength at the opening coupling portions of the two case members. Thus, large coupling portions are required. Although not specifically shown in JP-A-2004-001708, there arises a need to provide flanges to couple the case members together with bolts.
However, when adopting such a structure, the rotary electrical machine case itself consists of a plurality of members, which causes the shape of a case exterior to become complicated, and the size of the device becomes large at the same time, which is unfavorable.